1. Field of the Invention
The present invention relates to the medical treatment of varicose veins, and more specifically to a non-invasive, topical treatment for varicose veins utilizing the device described herein to act as an external one-way valve to replace the function of the defective internal valves contained within the varicose veins to be treated. This non-invasive treatment improves blood flow in the varicose veins and diminishes the vein varicosities without the necessity for an invasive and costly surgical procedure, the scarring which often results post-operatively from such procedures, the recurrence of varicosities which often follows such procedures, or the other undesirable effects of presently available treatments for varicose veins. This non-invasive treatment differs from other available treatments in that unlike such treatments, it restores rather than obliterates venous function.
2. Description of Varicose Vein Treatments and Related Art
Varicose veins is a medical condition which involves the abnormal twisting, lengthening or dilation of the superficial veins of the leg. It has been estimated that between 20% to 30% of the adult population suffers from some form and degree of varicose veins. Significant varicosities, those which are large enough for treatment, have been estimated to occur in about 12% of the adult population. Patients suffering from varicose veins often suffer from a variety of symptoms including aching, swelling, burning, throbbing and cramping in and around the areas in which the varicosities exist. These symptoms are felt much more intensely by women during pregnancy or during or just before menstruation. One survey showed that 50% of persons with varicose veins were bothered by their symptoms occasionally, and that 18% noted frequent to continuous symptoms. More serious complications may also result from the presence of varicose veins including phlebitis, ulceration, eczema, dermatitis and two-fold to four-fold increased risk of deep vein thrombosis. Even in the absence of such symptoms or more serious complications relating to the varicosities, many varicose vein sufferers seek medical treatment for the condition due to unsightliness of the varicosities.
The venous system of the legs consists of two channels: one deep within the muscular system and one superficial to it. The deep veins and the superficial veins are connected through a series of communicating veins, also called perforating veins. The superficial veins function mainly to collect blood from the subcutaneous tissue and to carry it to the closest communicating vein for rapid transit through the deep veins back to the heart. Approximately 15% of the venous blood volume in the legs is contained in the superficial veins, with 85% in the deep vein system.
One-way, bicuspid valves are located in the superficial veins that, when properly functioning, permit unidirectional flow of blood from the superficial venous system into the deep system to permit proper and rapid transmission of blood to the heart. These valves also break-up the otherwise continuous column of blood leading to the heart and thus reduce the hydrostatic pressure on the veins.
The cusps of the superficial venous valves are attached to the walls of the veins. Due to defective structure or function of the valves within the saphenous veins, intrinsic weakness of the vein walls, or the effects of a traumatic event which has significantly increased the blood pressure in the superficial veins (pregnancy being by far the single most significant such event), the valves of the saphenous veins become incompetent, permitting bidirectional flow (backflow or reflux) of blood through the veins with a corresponding increase in retrograde pressure in such veins. Regardless of the original cause of the valve incompetency, the result is the enlargement of the saphenous veins which, lying close to the skin and being poorly supported by the subcutaneous tissue, become varicose.
Once valve incompetence occurs, such as at valves on the upper thigh near the saphenous junction, and as blood refluxes, further venous enlargement occurs upstream (i.e., away from the heart and toward the feet), pulling the valve cusps further apart, causing more valvular incompetence in sections of the adjacent distal vein. As the segment of the engorged saphenous vein becomes elongated, the hydrostatic pressure exerted by the uninterrupted column of blood increases, further exacerbating the condition which causes the varicosities. With time, this process propagates into peripheral venous branches and also into communicating veins when they become exposed to the increased pressure from the continuous column of blood below an incompetent valve in the main saphenous channel. Moreover, in this condition, blood pressure during exercise fails to decrease normally because effective valves are not present.
Ebers in the papyrus of 1550 B.C. first described the condition of varicose veins and advised that surgery should not be performed. Caius Marius in Plutarch""s Lives underwent surgical correction of the varicose veins in one of his legs, but when questioned regarding similar treatment for the other leg, declined by noting, xe2x80x9cI see the cure is not worth the pain.xe2x80x9d For more than three thousand years, suffers of varicose veins have wrestled with the problem, attempting to avoid surgical repair of the condition while seeking less intrusive and more effective management methods for the condition.
There are currently three known types of treatment for varicose veins: (1) surgical vein ligation or stripping; (2) sclerotherapy: and (3) compression therapy. Surgical therapy in the form of vein stripping is directed at ligating the varicose system at its origin and removing the veins to prevent persistent reflux by direct and collateral routes. In the stripping technique, a small incision is placed at the distal end of the vein near the groin. The saphenous vein is also ligated at the foot. An internal vein stripper is then advanced proximally through the incision at the groin and secured. The stripper is then gently removed through the incision at the groin. It is also necessary for the surgeon to make multiple small incisions along the leg in order to disconnect the numerous communicating veins from the saphenous vein and to ligate these communicating veins. Postoperatively, the leg is wrapped and ambulation is held to a minimum for 8 to 12 hours. Complete recovery from varicose vein stripping usually takes 2 to 3 weeks. While saphenous vein stripping can often be accomplished without the use of a general anesthetic and without overnight hospitalization, particularly with the advent of ambulatory phlebectomy, a European developed varicose vein stripping procedure, a spinal or epidermal anesthetic is required. Surgical treatment of varicose veins may also be accomplished by vein ligation alone. While this procedure may be cost effective, studies have shown that it may not yield positive long term results due to extremely high rates of recurrence.
While stripping techniques represent a permanent solution in the area where the removed veins existed, the technique has numerous drawbacks. First, recurrence can occur in other areas of the leg away from the removed veins, and studies have shown recurrence rates from 12 to 56% over a five year period for patients who underwent vein stripping. Second, the procedure results in scarring which may be as cosmetically unsatisfactory as the varicose veins themselves. Third, a variety of complications can result from the procedure including infection, cutaneous pigmentation, superficial thrombophlebitis, deep venous thrombophlebitis, and nerve injury. Finally, if the veins are removed, they are unavailable should they be needed for arterial reconstruction, since the saphenous veins are normally used in such procedures.
Sclerotherapy involves injecting a liquid into the varicose veins that induces inflammation and scarring or sclerosis sufficient to seal the vein closed, which forces blood flow away from the affected veins. Various methods of sclerotherapy involve differing sclerosing agents combined with various levels of compression therapy to optimize efficacy.
In general, after careful mapping of the involved veins, a small gauge needle on a syringe containing the sclerosing agent is inserted into the vein while the leg is dependent. The syringe is taped to the leg while two or three other veins are punctured in the same manner. The leg is then elevated to empty the veins and the sclerosing agent is applied at each site. At the completion of the injections, a firm elastic bandage is wrapped carefully from the foot to 6 inches above the most proximal injection site. Some physicians recommend continuous compression for as long as 6 weeks. After compression has ended, the patient returns to the physician""s office for removal of the bandages and inspection of the results. Further injections can then be made, and the cycle can be repeated until the varicosities are gone.
While sclerotherapy is less expensive than vein stripping or ligation and is less invasive than such surgical procedures, it also has severe drawbacks. First, since it does not involve the removal of the affected veins, sclerotherapy may not represent a permanent or complete management technique. Studies have shown that the five year recurrence rate in small superficial or lower-leg communicating veins was 19%, while recurrence over that same period in large main venous trunks was 69%. Second, various complications can arise from the therapy, though most are minor and severe complications are rare. Third, it is often necessary for patients to undergo multiple courses of therapy to obtain sufficient results. Finally, as with stripping of the veins, sclerotherapy makes the veins unavailable for use in subsequent reconstructive procedures.
Finally, varicose veins may be xe2x80x9cconservativelyxe2x80x9d managed by the employment of compression therapy. Compression of the varicose vein occludes the vein, eliminating temporarily not only backflow of blood through the vein away from the heart but also flow in the normal direction toward the heart. Among compression measures, the most common is the elastic stocking, numerous brands and styles of which are commercially available and which are widely described in the literature such as by Lubin, U.S. Pat. No. 366,590; Teufel, U.S. Pat. No. 967,585; Scholl, U.S. Pat. No. 2,646,797; Westlake, U.S. Pat. No. 4,513,740; Daneshvar, U.S. Pat. No. 5,520,630; Fujimoto, U.S. Pat. No. 5,263,923; and Arabeyre et al. U.S. Pat. No. 5,497,513. While compression therapy is non-invasive, and therefore less painful than surgery or sclerotherapy, and considerably less expensive than such treatments, compression stockings are uncomfortable (particularly in warm weather), often don""t provide the desired effect and are as unsightly as the varicose veins to be treated.
Also known in the art is a variation on compressive therapy whereby a varicose vein is occluded by means of a tourniquet-like leg wrapping. Schutz et al., U.S. Pat. No. 519,894 discloses a strap for treatment of varicose veins whereby sufficient pressure is applied to a varicose vein so as to prevent retrograde blood flow (backflow) but which also prevents flow of blood in the normal direction toward the heart as a result of peripheral venous pumping caused by the action of the major muscles in the leg.
Compression therapies, focusing on the utilization of stockings of varying external compression can be useful in providing temporary relief, particularly to pregnant women in the third trimester of pregnancy but are normally ineffective as a long term treatment for the reasons stated above. Moreover, when compressive therapies provide sufficient pressure to prevent xe2x80x9cbackflow,xe2x80x9d they also prevent the beneficial flow of blood in the desired direction toward the heart.
The prior art relating to the treatment of varicose veins specifically and the use of pressure to treat venous and other ailments in general is directed to the simple concept of venous occlusion or removal to restrict venous blood flow to the exclusion of proper venous function. Ligation, stripping, and scierotherapy permit treatment of the varicose vein by its pennanent destruction and are inconsistent with the restoration of proper venous function. Compression therapy while attempting to accomplish a similar goal as more permanent varicose vein management measures are nevertheless temporary and are equally antithetical to restoration of venous function.
Given the severe drawbacks which exist in all of the presently available treatments for varicose veins, and in light of the historic search for an acceptable, non-invasive treatment for this condition, it is plain that a critical need exists for alternative treatments. Moreover, and perhaps of equal importance is the need for an effective treatment alternative which focuses on restoring proper venous function, rather than focusing on the obliteration or removal of the venous structures or the negation of their proper function.
The present invention provides improved methods and devices for the treatment of varicose veins wherein the function of the one-way valves in the varicose vein is replaced or supplemented by means of a device according to the invention which applies external pressure to the varicose vein in a manner which allows for flow in the normal direction toward the heart as a result of peripheral venous pumping but substantially reduces backflow away from the heart due to gravity. Specifically, the invention provides a device for treatment of a varicose vein of a subject comprising: (a) means for securing said device to the leg of a subject superficial to said vein to be treated; and (b) means for applying a selected amount of pressure to the skin superficial to said vein to be treated in a manner such that blood-flow toward the heart is permitted during peripheral venous pumping but wherein backflow away from the heart as a result of gravity is reduced. According to a preferred embodiment, a base which supports the means for applying pressure is attached to said securing means wherein the base is capable of traversing the skin superficial to said vein to be treated in a manner in which substantial downward pressure is not applied by the base to the skin superficial to said vein to be treated.
According to one embodiment of the invention, the means for applying pressure is a cantilever element such as a hinged strip of plastic which is attached to the base and which is biased by means such as a spring against the skin superficial to the vein to be treated. The biasing means is preferably a spring extending from the base which spring exerts force on the cantilever element which displaces the proximal wall of the vein toward the distal wall to form a junction closing the vein. According to one aspect of the invention, the cantilever element extends from the base in a direction toward the heart and exerts pressure on the vein at an angle such that venous pressure on the side of said junction distal from the heart exerts greater effective force displacing said strip than does venous pressure on the side of the junction proximal to the heart. In this manner, pressure on the valve resulting from peripheral venous pumping by contraction of the leg muscles such as occurs during walking will open the valve allowing blood to flow toward the heart. However, the pressure exerted against the cantilever element caused by the gravitational force on the head of the column of blood between the heart and the cantilever element of the invention will ordinarily be insufficient to displace the cantilever element and allow substantial backflow (retrograde flow) down the vein.
According to an alternative embodiment, the means for applying pressure is in the form of a wedge which can be biased against the skin by means such as a spring or can be made of a resilient material which exerts pressure against the skin. Such a wedge is preferably designed and disposed in a fashion wherein the apex of the wedge displaces the proximal wall of the vein toward the distal wall to form a junction closing the vein and wherein the wall of the wedge on the side of the apex away from the heart is disposed at an angle from the plane of the vein which is less than the angle from the plane of the vein of the wedge wall on the side of the apex toward the heart.